DESCRIPTION: This study evaluates the effectiveness of an assisted self-help intervention for smokeless tobacco (SLT) cessation. The primary aim is to evaluate sustained (6-week and 12-month) cessation effects of the intervention. Secondary aims include assessment of the spontaneous quit rate by conducting a random-digit-dialed telephone survey of SLT users in Oregon, Washington, and Idaho; comparison of intervention quit rates with estimates from the telephone survey; assessment of the relationship between baseline demographic and psychosocial variables and SLT cessation and maintenance; economic analysis to determine relative cost-effectiveness, assessment of the impact of other tobacco use on SLT cessation, and process evaluation of intervention components. Subjects will be recruited from three Northwest states, and adults who express an interest in quitting their use of SLT will be screened by telephone for eligibility. Eligible subjects (estimated N 1,026) will be randomized to receive either (1) a self-help manual only (control), or (2) a self-help manual, a video tape on quitting, and two supportive phone calls (Assisted Self-Help condition). In Phase One of the study, the intervention and assessment will be developed and piloted. Phase Two will involve subject recruitment, randomization of subjects to the two conditions, and intervention and assessment. Phase Two also includes a random-digit-dialed telephone survey to interview 1,100 SLT users about current use, quit attempts, and interest in quitting. Phase Three involves one-year follow-up with all intervention subjects and with phone survey participants who were SLT users at baseline. Phase Four involves analysis of results, preparation of manuscripts, and revision of materials for dissemination. Data from this study can significantly contribute to our understanding of how to provide effective, low-intensity programs to help adults quit their use of snuff or chewing tobacco.